Export (0) Print
Expand All

NodeLabelEditEventArgs Class

Provides data for the BeforeLabelEdit and AfterLabelEdit events.

For a list of all members of this type, see NodeLabelEditEventArgs Members.

System.Object
   System.EventArgs
      System.Windows.Forms.NodeLabelEditEventArgs

[Visual Basic]
Public Class NodeLabelEditEventArgs
   Inherits EventArgs
[C#]
public class NodeLabelEditEventArgs : EventArgs
[C++]
public __gc class NodeLabelEditEventArgs : public EventArgs
[JScript]
public class NodeLabelEditEventArgs extends EventArgs

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

The AfterLabelEdit event occurs when the user finishes editing the text for a tree node. The BeforeLabelEdit event occurs when the user begins editing the text for a tree node. A NodeLabelEditEventArgs object specifies the new text to associate with the tree node, the tree node that contains the label to edit, and whether the edit operation has been canceled.

For more information about handling events, see Consuming Events.

Example

[Visual Basic, C#, C++] The following example allows the user to edit nonroot tree nodes by using a ContextMenu. When the user right clicks the mouse, the TreeNode at that position is determined and stored in a variable named mySelectedNode. If a nonroot tree node was selected, it is put into an editable state, allowing the user to edit the node label. After the user stops editing the tree node label, the new label text is evaluated and saved. For this example, several characters are considered not valid in the label text. If one of the invalid characters is in the label string, or the string is empty, the user is notified of the error and the label is returned to its previous text.

[Visual Basic] 
' Get the tree node under the mouse pointer and
' save it in the mySelectedNode variable. 
Private Sub treeView1_MouseDown(sender As Object, _
  e As System.Windows.Forms.MouseEventArgs)
        
   mySelectedNode = treeView1.GetNodeAt(e.X, e.Y)
End Sub    
    
Private Sub menuItem1_Click(sender As Object, e As System.EventArgs)
   If Not (mySelectedNode Is Nothing) And _
     Not (mySelectedNode.Parent Is Nothing) Then
      treeView1.SelectedNode = mySelectedNode
      treeView1.LabelEdit = True
      If Not mySelectedNode.IsEditing Then
         mySelectedNode.BeginEdit()
      End If
   Else
      MessageBox.Show("No tree node selected or selected node is a root node." & _
        Microsoft.VisualBasic.ControlChars.Cr & _
        "Editing of root nodes is not allowed.", "Invalid selection")
   End If
End Sub    
    
Private Sub treeView1_AfterLabelEdit(sender As Object, _
  e As System.Windows.Forms.NodeLabelEditEventArgs)
   If Not (e.Label Is Nothing) Then
      If e.Label.Length > 0 Then
         If e.Label.IndexOfAny(New Char() {"@"c, "."c, ","c, "!"c}) = -1 Then
            ' Stop editing without canceling the label change.
            e.Node.EndEdit(False)
         Else
            ' Cancel the label edit action, inform the user, and
            ' place the node in edit mode again. 
            e.CancelEdit = True
            MessageBox.Show("Invalid tree node label." & _
              Microsoft.VisualBasic.ControlChars.Cr & _
              "The invalid characters are: '@','.', ',', '!'", _
              "Node Label Edit")
            e.Node.BeginEdit()
         End If
      Else
         ' Cancel the label edit action, inform the user, and
         ' place the node in edit mode again. 
         e.CancelEdit = True
         MessageBox.Show("Invalid tree node label." & _
           Microsoft.VisualBasic.ControlChars.Cr & _
           "The label cannot be blank", "Node Label Edit")
           e.Node.BeginEdit()
      End If
         Me.treeView1.LabelEdit = False
   End If
End Sub 

[C#] 
/* Get the tree node under the mouse pointer and 
   save it in the mySelectedNode variable. */
private void treeView1_MouseDown(object sender, 
  System.Windows.Forms.MouseEventArgs e)
{
   mySelectedNode = treeView1.GetNodeAt(e.X, e.Y);
}

private void menuItem1_Click(object sender, System.EventArgs e)
{
   if (mySelectedNode != null && mySelectedNode.Parent != null)
   {
      treeView1.SelectedNode = mySelectedNode;
      treeView1.LabelEdit = true;
      if(!mySelectedNode.IsEditing)
      {
         mySelectedNode.BeginEdit();
      }
   }
   else
   {
      MessageBox.Show("No tree node selected or selected node is a root node.\n" + 
         "Editing of root nodes is not allowed.", "Invalid selection");
   }
}

private void treeView1_AfterLabelEdit(object sender, 
         System.Windows.Forms.NodeLabelEditEventArgs e)
{
   if (e.Label != null)
   {
     if(e.Label.Length > 0)
     {
        if (e.Label.IndexOfAny(new char[]{'@', '.', ',', '!'}) == -1)
        {
           // Stop editing without canceling the label change.
           e.Node.EndEdit(false);
        }
        else
        {
           /* Cancel the label edit action, inform the user, and 
              place the node in edit mode again. */
           e.CancelEdit = true;
           MessageBox.Show("Invalid tree node label.\n" + 
              "The invalid characters are: '@','.', ',', '!'", 
              "Node Label Edit");
           e.Node.BeginEdit();
        }
     }
     else
     {
        /* Cancel the label edit action, inform the user, and 
           place the node in edit mode again. */
        e.CancelEdit = true;
        MessageBox.Show("Invalid tree node label.\nThe label cannot be blank", 
           "Node Label Edit");
        e.Node.BeginEdit();
     }
     this.treeView1.LabelEdit = false;
   }
}

[C++] 
/* Get the tree node under the mouse pointer and 
   save it in the mySelectedNode variable. */
private:
void treeView1_MouseDown(Object* /*sender*/, 
  System::Windows::Forms::MouseEventArgs* e)
{
   mySelectedNode = treeView1->GetNodeAt(e->X, e->Y);
}

void menuItem1_Click(Object* /*sender*/, System::EventArgs* /*e*/)
{
   if (mySelectedNode != 0 && mySelectedNode->Parent != 0)
   {
      treeView1->SelectedNode = mySelectedNode;
      treeView1->LabelEdit = true;
      if(!mySelectedNode->IsEditing)
      {
         mySelectedNode->BeginEdit();
      }
   }
   else
   {
      MessageBox::Show(S"No tree node selected or selected node is a root node.\nEditing of root nodes is not allowed.", S"Invalid selection");
   }
}

void treeView1_AfterLabelEdit(Object* /*sender*/, 
         System::Windows::Forms::NodeLabelEditEventArgs* e)
{
   if (e->Label != 0)
   {
     if(e->Label->Length > 0)
     {

        Char temp0 [] = {'@', '.', ',', '!'};
        if (e->Label->IndexOfAny(temp0) == -1)
        {
           // Stop editing without canceling the label change.
           e->Node->EndEdit(false);
        }
        else
        {
           /* Cancel the label edit action, inform the user, and 
              place the node in edit mode again. */
           e->CancelEdit = true;
           MessageBox::Show(S"Invalid tree node label.\nThe invalid characters are: '@','.', ',', '!'", 
              S"Node Label Edit");
           e->Node->BeginEdit();
        }
     }
     else
     {
        /* Cancel the label edit action, inform the user, and 
           place the node in edit mode again. */
        e->CancelEdit = true;
        MessageBox::Show(S"Invalid tree node label.\nThe label cannot be blank", 
           S"Node Label Edit");
        e->Node->BeginEdit();
     }
     this->treeView1->LabelEdit = false;
   }
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Windows.Forms

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: System.Windows.Forms (in System.Windows.Forms.dll)

See Also

NodeLabelEditEventArgs Members | System.Windows.Forms Namespace | NodeLabelEditEventHandler | BeforeLabelEdit | AfterLabelEdit

Show:
© 2014 Microsoft